C ++重载加法运算符以添加对象

Question

I'm working on a project where I need to add two objects together by overloading the addition operator, 99% of it makes sense to me, but I can't figure out how to do the actual addition process.

My code is currently

Time operator+(const Time& t1)
{
     int num = this.milliseconds + t1.milliseconds;
     Time t(num);
     return t;
}

Then I call it like so

t4 = t1 + t2;

I thought using this.milliseconds would allow me to access t1 's int variable but it won't allow me.

Basically my question is how do I access the time variable on the left of the + operator since I only pass the operator+ function one object of Time? (t2)

Answer 1

If your operator+ is a member function of the Time class then you should be able to access its fields when you change this.milliseconds to this->milliseconds or just milliseconds . Please note that this is a pointer so it requires the -> operator.

You don't have to be concerned about the operator+ having only one parameter. If you overload a two argument operator as a class member then it is implicitly assumed that the first argument of the operator is this .

You have also a possibility to overload an operator as a non-member function and then you have to specify two parameters like this: Time operator+(const Time& t1, const Time& t2) .

It is also worth mentioning that your operator+ could be a const member function.